<template>
  <div>
    <div class="subject" v-for="(item, index) in SubjectList" :key="index">
      <span>{{ item.num1 }}</span>
      <span>+</span>
      <span>{{ item.num2 }}</span>
      <span>=</span>
      <input type="number" v-model.number="item.key" />
      <button @click="submit(index)">提交</button>
    </div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      SubjectList: []
    }
  },
  created() {
    this.getRandomNum()
  },
  methods: {
    getRandomNum() {
      let num1, num2
      for (let i = 0; i < 5; i++) {
        num1 = Math.floor(Math.random() * 100)
        num2 = Math.floor(Math.random() * 100)
        this.SubjectList.unshift({
          num1,
          num2,
          result: num1 + num2
        })
      }
    },
    submit(index) {
      this.$emit('submit', this.SubjectList[index].result, this.SubjectList[index].key)
    }
  }
};
</script>

<style scoped>
.subject {
  margin: 5px;
  padding: 5px;
  font-size: 20px;
}

.subject span {
  display: inline-block;
  text-align: center;
  width: 20px;
}

.subject input {
  width: 50px;
  height: 20px;
}
</style>